Chimichurri sauce : combine the following in a food processor -
4 large garlic cloves
3 tablespoons red wine vinegar
1/2 teaspoon red pepper flakes
1/2 teaspoon fresh ground black pepper
1/4 cup olive oil
1/2 to 3/4 cup chopped flat-leaf parsley
3/4 teaspoon salt
I suggest you play with the proportions until you achieve a taste you like. The mixture should be spicy and salty with a bit of tang.
Marinate flank steak in a few tablespoons of the sauce for about 30 minutes. While the steak is marinating, halve some small waxy potatoes and place in a pan with cold water to cover. Add a liberal amount of salt, bring to a boil and simmer until potatoes are just tender. Remove from water and immediately toss with a tiny bit of olive oil then place in a medium-hot grill pan for about 3 minutes (so that grill marks appear and cut surfaces become slightly crispy). Keep warm until ready to serve.
Cook flank steaks in a medium hot grill pan for about 3 to 4 minutes on each side, depending on the thickness of the meat and level of doneness required.
Slice steaks across the grain and serve on a bed of salad greens with potatoes and torn or shredded pieces of bocconcini. Drizzle a bit more chimichurri on top.
Leftover chimichurri will keep for a few days in the fridge, and can be served with fish, chicken, eggs or veggies.